Method for inserting a crt mask into its mating panel

ABSTRACT

Apparatus and method for the automatic insertion of a cathode ray tube shadow mask into a mating front panel. The apparatus includes means for aligning the shadow mask such that the mask alignment holes are positioned at points which lie in a substantially horizontal hole reference plane with each hole positioned at a predetermined location, and means for engaging the panel studs and aligning the panel by means of the studs to a position where the studs are located at points which lie in a substantially horizontal stud reference plane and at a location within that plane which places each stud in vertical alignment with and at a predetermined distance above its corresponding mask alignment hole. With the shadow mask and its panel in positions of alignment, the mask springs are compressed to permit insertion of the mask assembly into the panel, the mask is raised the predetermined distance between the hole reference plane and the stud reference plane, and the springs are released to permit engagement between each stud and its corresponding alignment hole.

United States Patent 1 Baranski et al.

[ Oct. 1,1974

1 METHOD FOR INSERTING A CRT MASK INTO ITS MATING PANEL [75] Inventors: Ronald S. Baranski, Round Lake;

Leslie L. Baur, Glen Ellyn Countryside, both of I11.

[73] Assignee: Zenith Radio Corporation, Chicago,

[22] Filed: Oct. 26, 1973 [21] Appl. No.: 410,142

[56] References Cited UNITED STATES PATENTS 11/1966 Prazak 29/203 .1 X 9/1969 Kautz 29/25.15

Primary Examiner-Roy Lake Assistant Examiner-James W. Davie Attorney, Agent, or Firm.lohn H. Moore [57] ABSTRACT Apparatus and method for the automatic insertion of a cathode ray tube shadow mask into a mating front panel. The apparatus includes means for aligning the shadow mask such that the mask alignment holes are positioned at points which lie in a substantially horizontal hole reference plane with each hole positioned at a predetermined location, and means for engaging the panel studs and aligning the panel by means of the studs to a position where the studs are located at points which lie in a substantially horizontal stud reference plane and at a location within that plane which places each stud in vertical alignment with and at a predetermined distance above its corresponding mask alignment hole. With the shadow mask and its panel in positions of alignment, the mask springs are compressed to permit insertion of the mask assembly into the panel, the mask is raised the predetermined distance between the hole reference plane and the stud reference plane, and the springs are released to permit engagement between each stud and its corresponding alignment hole.

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METHOD FOR INSERTING A CRT MASK INTO ITS MATING PANEL BACKGROUND OF THE INVENTION Conventional color cathode ray tubes are constructed of several major components including an aperture mask, a phosphor coated front panel, and a glass. funnel-like envelope which is frit-sealed to the front panel. The panel has a l /2 to 3 inch wrap-around skirt in which a number of alignment studs (usually 3) are embedded. The mask assembly includes a corresponding number of springs mounted on the sides of the mask assembly. Each spring has an alignment hole in one end thereof for engagement with a panel stud.

When the tube has been assembled, the aperture mask is situated within the front panel and securely fastened thereto by the engagement of the panel alignment studs with the mask alignment holes. Thus, the mask assembly can be removed from the panel by compressing the leaf springs and disengaging the alignment studs from the holes.

In the production of cathode ray tubes, each panel is mated with a particular mask to insure that the pattern of apertures in the mask correspond precisely to the phosphor pattern deposited on the inside surface of the panel. In the process of establishing a tri-colored phosphor pattern, the panel is first coated with a photosensitized phosphor slurry, the mask is inserted into the panel, and a source of actinic light is directed through the mask apertures. Those preselected areas of the phosphor coating which are thus exposed to the actinic light are rendered insoluble in water while the nonexposed areas remain soluble. During this exposure, the aperture mask must be securely in place within the panel.

The next processing step is to remove the mask from the panel and treat the exposed panel surface with a solvent to wash away the soluble slurry from those areas of the mask which have not been exposed. The result is a panel covered with an array of phosphor elements which corresponds to the aperture array of the mask.

This entire procedure must be repeated for each of the three colored phosphors. Obviously, the aperture mask must be inserted into the panel and removed therefrom several times during the processing of the front panel. Because the aperture mask is only seven mils thick, it is easily dented and mishapen by accidental bumping and mishandling. Should an aperture mask become bent or dented, it and its corresponding panel must be scrapped because even small dents can cause substantial misregistration between the phosphor pattern on the front panel and the aperture pattern on the mask.

Up until now, the masks have been inserted and removed from their respective front panels manually. This manual insertion and removal of the mask is not only time consuming but gives rise to mishandling. In addition, since the front panel is normally in a horizontal position with its phosphor coated surface facing upwardly during insertion and removal of the panel, it is possible for human hair, lint, etc., to fall into the mask or into the panel itself. Such undesirable elements tend to contaminate either the mask or the panel and can result in a subsequently rejected cathode ray tube.

To overcome the inherent difficulties of manual insertion of the aperture mask into the panel. it is desirable to have means for automatically effecting such in sertion. While the likely benefits of automatic mask insertion have been long appreciated, no commercially practical apparatus for accomplishing it has, up until now, been made. Part of the problem with effecting the automatic machine insertion of a mask into a panel arises because of the fact that each mask alignment hole should be in precise registry with its mating panel alignment stud before they may be properly engaged. However, the alignment holes and studs for a particular mask panel pair are not precisely enough located on their respective supporting structures to permit a machine to perform a standard insertion maneuver and guarantee that each mask panel pair will be properly mated. This problem, in addition to the requirement that an automatic machine insertion device be fast enough to keep up with other cathode ray tube production equipment, has forestalled the use of such devices in commercial production applications.

OBJECTS OF THE INVENTION It is a general object of this invention to provide automatic apparatus and method for inserting a color cathode ray tube shadow mask into its mating front panel.

It is a more specific object of this invention to provide method and apparatus capable of effecting rapid and precise automatic mask to panel insertion while accounting for location tolerances in both the panel studs and the mask alignment holes.

Prior Art US. Pat. No. 3,284,884 issued to C]. Prazak III, US. Pat. No. 3,482,286 issued to G.L. Fassett et a1,

and

US. Pat. No. 3,653,112 issued to CL. Smith et al.

BRIEF DESCRIPTION OF THE DRAWINGS The features of this invention, which are believed to be new are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may best be understood by reference to the following description in conjunction with the accompanying drawings in which like reference numerals refer to like elements and in which:

FIG. 1 illustrates a cathode ray tube front panel and shadow mask and certain features thereof useful in explaining the invention;

FIG. 2 schematically illustrates the way in which the preferred embodiment implements the principles of this invention;

FIG. 3 is a perspective view of the preferred embodiment of this invention;

FIGS. 4 and 4A are sectional views showing some internal elements of the preferred embodiment;

FIG. 5 is a view of the preferred embodiment taken along section lines X in FIG. 3;

FIG. 6 is a simplified top view of the FIG. 3 embodiment showing certain internal elements of the preferred embodiment;

FIGS. 7 and 8 are partial sectional views showing particular aspects of the FIG. 3 embodiment;

FIG. 8A is a sectional view taken along lines 8A of FIG. 8;

FIG. 8B is a view of a particular element of the preferred embodiment which differs from a similar element shown in FIG. 8A;

FIG. 8C is a sectional view taken along lines SC in FIG. 8;

FIGS. 9 and 10 are partial sectional views of the preferred embodiment; and

FIGS. 11A through 11E are simplified drawings howing a sequence of operations by which a shadow mask is aligned and mated to a front panel.

DESCRIPTION OF THE'PREFERRED EMBODIMENT In order to better understand the various features of this invention and its preferred embodiment, a typical cathode ray tube front panel and mask assembly will be examined in order to point out the inherent difficulties in automatically mating the panel with the mask.

As shown in FIG. 1, the mask assembly 10 consists of an apertured mask 12 mounted on a mask frame 14. Attached to frame 14 are three springs 16. One end of each spring is welded to the frame while the other end is flexible and contains a mask alignment hole 18 which is used to align the mask assembly with a panel. Panel 20 includes a front plate 22 around which a skirt 24 is wrapped. Embedded in the inner surface of skirt 24 are three panel studs 26 which are intended to mate with the mask alignment holes 18.

In mating a mask assembly to a panel, springs 16 must first be compressed. The mask assembly is then inserted into the panel so that each mask alignment hole 18 is aligned with its corresponding stud 26. Springs 16 are then released to permit engagement between the panel studs 26 and mask alignment holes 18.

As pointed out in the discussion above, the insertion of a mask assembly into a panel is normally accomplished by hand. In spite of the disadvantages of manual insertion, this method of mating masks and panels has continued up until now because of the difficulty in automatically aligning the mask alignment holes 18 with the studs 26. This difficulty is due primarily to the fact that there is no convenient reference location on either a panel or a mask assembly from which to determine precisely where the studs 26 or the mask alignment holes 18 should be located. Due to production tolerances, one cannot assume that any particular mask alignment stud is located at a standard point on the panel skirt 24. Rather loose tolerances on the locations at which the springs 16 are welded to the mask frame 14 preclude an assumption that mask alignment holes 18 are precisely located at a predeterminable position with respect to the frame 14. An accumulation of these rather loose tolerances in the location of the alignment elements, i.e., panel studs and alignment holes, has pre vented the picture tube industry from producing amachine capable of automatically inserting, with any degree of consistency, the mask assemblies into their respective panels.

According to this invention the panel studs 26 and mask alignment holes 18 are brought into alignment with each other by applying alignment forces directly onto each alignment stud 26 and each mask alignment hole 18. In this way there is little or no dependence upon close tolerances with respect to the relative posi- The way in which such alignment is accomplished may best be explained by reference to FIG. 1 noting in particular the arrowheads directed toward representative mask alignment holes 18 and panel studs 26. These arrowheads are vector representations of some of the alignment forces which are applied to each of the alignment elements.

First, forces are applied to each mask alignment hole 18 to locate the center of each such hole in a first substantially horizontal reference plane, with each hole positioned at a predetermined location in that plane. Next, the panel 20 is positioned and supported in a horizontal position above the mask assembly 10. The, in a manner to be described below, each stud 26 is captured so that horizontal and vertical alignment forces may be applied thereto to place each stud in a second substantially horizontal plane parallel to the first reference plane in which the centers of the mask alignment holes 18 are positioned. The vertical alignment forces which are applied to each stud 26 place each stud at a predetermined common vertical distance from its respective mask alignment hole. This distance is labeled D in FIG. 1.

With the mask alignment holes 18 and the studs 26 each placed in substantially parallel planes, each alignment element in vertical alignment with its respective mating element, and with a known distance D separating the corresponding alignment elements, the panel and mask assembly are then mated by compressing the mask springs 16 to allow insertion of the mask assembly into the panel, effecting relative vertical movement over the predetermined distance D between the mask assembly and the panel to place the studs 26 and the mask alignment holes 18 in substantially horizontal alignment, and releasing the springs to permit engage- I ment between each stud 26 and its corresponding mask tion of a stud with its panel or a mask alignment hole with its mask assembly.

alignment hole 18.

By following the preceding sequence of steps, a panel and a mask assembly may be automatically mated without relying on closetolerances to place a mask alignment hole 18 or a panel stud 26 at a precisely known location on the mask assembly 10 or the panel 20.

One way in which the above-described mask insertion procedure may be accomplished is illustrated schematically in FIG. 2. The various elements shown therein and their functions will now be described in a sequence which corresponds to the sequence of operations which occurs when using the illustrated elements to automatically insert a shadow mask into a front panel. In the description immediately below, reference is made to certain elements which appear more than once in the preferred embodiment. However, for the sake of simplifying the FIG. 2 drawing and its explanation, only a representative one of each such elements is shown. An explanation of the structural details of the various elements will be deferred and included in a more detailed description of the preferred embodiment to follow.

As shown in FIG. 2, a front panel 20 rests upon a number of floating pads 40 which are spring-biased to remain flush against the panel's lower surface or seal land 56. A platen 30 is provided to support mask assembly 10 and has four ,upwardly protruding mask guides 32 which assist in roughly locating the mask in its correct position on platen 30. A platen lifting cylinder 34 raises and lowers platen 30 between a lowered position as shown and an elevated position where the platen is near the top surface of pad 40.

For purposes of explanation, assume that cylinder 34 has extended so as to lift platen 30 to its elevated position. It is in that raised position that platen 30 is ready to accept to mask assembly. I

After a mask assembly has been placed on platen 30. the operator depresses two push buttons (not shown) in order to cause platen lifting cylinder 34 to retract. This places platen 30 and mask assembly in the position which is shown in FIG. 2.

The next step is the placing of the panel upon panel support areas 36 (not shown in FIG. 2) and upon four floating pads 40. The seal land 56 rests upon and depresses the lightly spring loaded floating pads 40. At this point the operator again presses the push buttons to initiate a sequence of automatic operations which will insert mask assembly 10 into panel 20 without further manual assistance.

The mask insertion machine begins the alignment of the mask assembly 10 and the panel 20 by first extending the driving arms 47 of three alignment cylinders 46. This action simultaneously causes the mask assembly 10 and the panel 20 to be shifted and lifted to predetermined alignment positions in the following manner. Three stud locating fingers 44 respond to the extension of arms 47 by pivoting upwardly about point A to engage the three panel studs 26 embedded in panel skirt 24. Each finger terminates in a V-shaped groove which captures a stud, shifts it to a predetermined alignment position and raises each stud to a predetermined position in a reference plane. Because the studs 26 have been thus raised somewhat, the entire panel is likewise raised, thus permitting the spring biased floating pads 40 to rise and follow the seal land 56. After the panel has been aligned so that each stud is placed in a predetermined position in a reference plane, and after floating pads 40 have risen to follow and remain flush with the seal land 56, the four pad locking cylinders 42 (only one is shown in FIG. 2) are activated and extend their driving arms upwardly. This forces member 58 to wedge block 60 firmly against rod 62. This engagement of block 60 with rod 62 fixes the position of rod 62 and therefore also the position of floating pad 40. The purpose of locking the pads 40 into this position is to maintain panel 20 in its elevated and aligned position after stud locating fingers 44 are subsequently disengaged from panel studs 26. The surfaces of floating pads 40 are preferably rubber coated to prevent vibrations from shifting panel 20 from its aligned position.

When alignment cylinders 46 were activated and caused stud locating fingers 44 to pivot upwardly, they also forced three hole locating pins 64 inwardly toward mask assembly 10. Pins 64 in turn engage mask alignment holes 18. When passing through holes 18, locating pins 64, tapered to permit full contact between the periphery of each locating pin 64 and the surrounding edges of alignment holes 18, lift and shift mask assembly 10 so that each alignment hole 18 is positioned in a hole reference plane substantially parallel to the plane in which studs 26 lie. Each alignment hole 18 is also shifted into vertical alignment with its corresponding panel stud.

Ultimately, pins 64 must be withdrawn from alignment holes 18 to permit the mask to be inserted into the panel. In order to hold the mask assembly in its aligned position after pins 64 have been withdrawn and in order to supply the necessary inward compression of springs 16 prior to mask insertion, three squeeze fingers 66 are provided. They are activated by a stepping motor 48 which drives cam 52. Cam 52 is linked to squeeze fingers 66 so as to cause fingers 66 to move inwardly toward the mask assembly 10. As fingers 66 encounter mask springs 16, they squeeze the springs against the mask frame 14 and hold the frame firmly in its aligned position. Thus when alignment cylinder 46 and hole locating pins 64 retract, mask assembly 10 will be held by squeeze fingers 66 in its aligned position.

After alignment cylinders 46 retract leaving panel 20 held in position by floating pads 40 and mask assembly 10 held in position by fingers 66, platen 30 is ready to be raised to place mask assembly 10 within panel 20. At this point, platen lifting cylinder 34 extends and raises platen 30 a predetermined height to place each alignment hole in horizontal alignment with its corresponding panel stud. When mask assembly 10 is thus positioned within panel 20, stepping motor 48 drives cam 52 and causes fingers 66 to move outwardly. This releases springs 16 and allows each mask alignment hole 18 to engage its corresponding panel stud. Platen lifting cylinder 34 then retracts and lowers platen 30, now empty, to a lowered position. The panel is then in condition to be removed from the mask insertion machine with its mask assembly inserted within.

Referring now to FIG.3, there is shown a perspective view of the preferred embodiment of this invention which incorporates the operational characteristics described above in connection with FIG. 2.

A main frame 28 providesthe structural support for the various members of this machine. Housed within frame 28 is platen 30 upon which a mask assembly is placed to begin the automatic sequence of mating a mask assembly with a panel. At the corners of platen 30, mask guides 32 are shown which help in roughly loeating the mask assembly at its proper position upon the platen. As described above, platen 30 is raised and lowered within frame 28 by means of a platen lifting cylinder 34 (not visible in FIG. 3).

Near the top of frame 28 there is provided a number of panel support areas 36 for receiving and supporting a panel with its skirt facing downwardly. Four panel guides 38 are disposed nearthe four corners of frame 28 to assist in roughly locating a panel at the proper location on the panel support areas.

The four spring-loaded floating pads 40 are located around the panel support areas 36 for holding a panel in an aligned position. Only two of the pads are visible in the view shown in FIG. 3. Beneath each floating pad 40 is a pad locking cylinder 42, activated by air pressure, which causes its associated floating pad to lock in a given position.

Three stud locating fingers 44 are disposed around the perimeter of frame 28 for locating and aligning the three panel studs 26. Associated with each stud locating finger 44 is an alignment cylinder 46 which actuates a stud locating finger 44 and a hole locating pin 64. Cylinder 46 and all other cylinders are actuated by air pressure from a pressurized air source (not shown).

Push buttons 50 are used to initiate an automatic sequence of operations which causes the panel and mask assembly to be mated. Preferably, two of push buttons 50 are required to be depressed to initiate the operation in order to insure that both the operators hands are clear of the movable elements of the machine.

Turning now to FIG. 4, a simplified sectional view of the mask insertion machine is shown with certain elements omitted for clarity and ease of explanation. In this case the platen lifting cylinder 34 is shown in a retracted position. The means by which fingers 66 are compressed is more clearly shown in this view. Each finger 66 is attached to a rod 94, one end of which is coupled to cam follower 70. Cam follower 70 follows a groove in cam 52 which is belt-driven by stepping motor 48. A more complete description of cam 52 and the way in which it controls fingers 66 will be given in the discussion to follow.

FIG. 4A, another simplified sectional view with certain elements omitted, indicates that platen 30, motor 48, fingers 66 and platform 54 are all raised together when cylinder 34 is extended. Mask assembly 10 is shown in a position of alignment with panel 20.

The FIG. 5 view, taken along section lines X in FIG. 3, illustrates the means by which squeeze fingers 66 are controlled. Motor 48 drives cam 52 by means of belt 86. When squeeze fingers 66 are to be drawn inwardly to squeeze the mask springs against the frame, cam 52 is caused to rotate clockwise as indicated by the arrow. Can followers 70 follow their respective grooves 88, 90 and 92 and cause squeeze rods 94 and squeeze fingers 66 to be drawn inwardly. Cam 52 is shown fully rotated clockwise.

Note that groove 90 is cut differently than grooves 88 and 92. As cam 52 is rotated clockwise, squeeze rods 94 associated with grooves 88 and 92 are drawn inwardly first. This causes squeeze fingers 66 on opposing sides of the mask assembly to squeeze their corresponding springs against the mask frame. Once the frame is held securely bythe opposing squeeze fingers 66, groove 90 causes the third squeeze rod to be pulled inwardly. The delayed action of groove 90 is intended toinsure that no unbalanced force is applied to mask assembly before it is held firmly in place in its aligned position. Otherwise, mask assembly 10 could possibly be moved out of alignment by a force against which no opposing force is exerted.

FIG. 6 shows squeeze fingers 66 extended after cam 52 has been rotated counterclockwise in order to release springs I6 and permit engagement between mask alignment holes 18 and alignment studs 26.

Refer now to FIG. 7 for the details of the way in which hole locating pins 64 and stud locating fingers 44 are actuated. Fingers 44 are coupled to driving arm 47 which is in turn coupled to piston 74 in cylinder 46. When piston 74 is caused to rise, fingers 44 are lifted and turned upwardly by the motion of driving arm 47 following groove 75 and by the pivoting motion permitted by groove 76 and pivot 78.

As piston 74 extends and arm 47 travels along groove 75, the bottom end of cylinder 46 pivots at 80 and allows cylinder 46 to lean to the left. This motion pushes against spring 82 and forces guide pin 84 and hole locating pin 64 to the left to engage mask alignment hole 18. FIG. 8 shows cylinder 46 in its extended position with stud locating fingers 44 engaging alignment stud 26 and hole locating pin 64 engaging mask alignment hole 18.

FIG. 8A is a view taken along lines 8A in FIG. 8. It illustrates the V notch at the end of stud locating finger 44 and its relative position to alignment stud 26 when the two are engaged.

The fingers which capture the two studs facing each other from opposing sides of a panel both have the V notch shape shown in FIG. 8A. However, the finger which captures the third stud preferably has a modified V notch such as that shown in FIG. 8B. Note that that notch has a flat portion upon which the captured stud may rest in contrast to the more narrow V shaped crevice of the FIG. 8A finger. The reason for having this flat portion in the third finger, is that it is unnecessary and expensive to accurately shape and position three stud locating fingers of the type shown in FIG. 8A to ensure that each panel stud is captured and shifted to an exact alignment location. By shaping the third finger, as in FIG. 8B, so as to allow some lateral movement of the third captured stud, the associated panel will come to rest in a position which is very accurately located. This can be appreciated by first realizing that the other two stud locating fingers position their captured studs in predetermined positions in both a vertical and a horizontal sense. This necessarily shifts the third stud to the only position in a horizontal plane which it can occupy. There is, therefore, no point in using a third finger which attempts to laterally shift that third stud.

FIG. 8C is a sectional view taken along lines 8C in FIG. 8. It shows the shape of squeeze finger 66 and its relative position with respect to hole locating pin 64.

FIG. 9 shows the structural details of the means by which floating pad40 is locked into position. After panel 20 has been raised to its aligned position by stud locating fingers 44, pad locking cylinder 42 extends as shown in FIG. 9 and forces member 58 upwardly. This action causes block 60 to wedge against rod 62 as shown and hold it and floating pad 40 in locked position. The cutout section of rod 62 at which the wedging occurs is tapered atapproximately 11 to insure that rod 62 is held firmly in place.

FIG. 10 shows floating pad 40 in a floating condition with no panel resting upon it and pad locking cylinder 42 retracted.

FIGS. 11A through 11E illustrate the relative positions of hole locating pins 64, squeeze fingers 66 and mask alignment holes 18 at various stages during the automatic insertion of the mask assembly into the panel. FIG. 11A shows the positions of the various alignment elements just prior to the alignment of the mask assembly 10. FIG. 11B illustrates how hole locating pins 64 engage alignment holes 18 to shift and lift mask assembly 10 to its predetermined alignment position. FIG. 11C indicates how squeeze fingers 66 compress mask springs 16 to hold mask assembly 10 in its aligned position and thereby permit insertion of the mask into the panel. FIG. 11D shows mask assembly 10 after it has been inserted into panel 20 and just prior to the reiease of springs 16 by squeeze fingers 66. FIG. 11E indicates how squeeze fingers 66 retract to allow springs 16 to flex outwardly and cause engagement between panel studs 26 and mask alignment holes 18.

Although the discussion above has, up to this point, been confined to a disclosure of means for automati' cally inserting a mask assembly into a panel, it is contemplated that this invention may also be used for the removal of a mask assembly from a panel. The only changes required in the preferred embodiment to effect this alteration in the function of the machine are those which relate to the sequencing of the various functional steps.

Thus, in accordance with the above set objectives, it has been shown that a cathode ray tube mask may be inserted into its panel automatically, notwithstanding the usual location tolerance problems associated with the mask alignment holes and the panel studs. The described apparatus can provide the desired insertion of masks at the rate of 240 per hour continuously, thereby increasing the efficiency of cathode ray tube productron.

While the invention has been described with specific embodiments thereof, it is evident that may alternations, modifications and variations will be apparent to those skilled in the art in light of the above disclosure. Accordingly, it is intended to embrace all such alterations, modifications and variations which fall within the spirit and scope of this invention as defined by the appended claims.

We claim: 1. A method of inserting a color cathode ray tube mask assembly into a cathode ray tube front panel having a wrap-around skirt with alignment studs protruding inwardly therefrom for engagement with alignment holes formed in leaf-type springs mounted on the mask assembly, comprising:

positioning the mask assembly such that the alignment holes are located at points which liein a substantially horizontal hole reference plane, each hole positioned at a predetermined location;

positioning and supporting the panel in a roughly horizontal position above the mask assembly;

engaging the studs and precisely aligning the panel by means of the studs to a position where the studs are located at points which lie in a substantially horizontal stud reference plane with each stud in vertical alignment with its respective mask alignment hole and at a predetermined common vertical distance above said hole;

compressing the mask springs to allow insertion of the mask assembly into the panel;

effecting relative vertical movement over said predetermined distance between the mask assembly and the panel for placing the studs and alignment holes in substantially horizontal alignment; and releasing the springs to permit engagement between each stud and its corresponding alignment hole.

2. A method as defined in claim 1, wherein the studs are located at a predetermined common vertical distance above their respective alignment holes by lifting each stud vertically a distance which effectively places it at a point which lies in the stud reference plane.

3. A method as defined in claim 1, wherein said mask assembly has two leaf-type springs mounted on opposing sides of the mask assembly and a third spring mounted on an adjacent side, each spring having a single alignment hole, and wherein the two opposing springs are compressed simultaneously and prior to the compression of the third spring.

4. A method of inserting a cathode ray tube mask assembly into a cathode ray tube front panel having a wrap-around skirt with alignment studs protruding inwardly therefrom for engagement with alignment holes formed in leaf-type springs mounted on the mask assembly, comprising:

positioning the mask assembly such that the alignment holes are located at points which lie in a substantially horizontal hole reference plane, each hole positioned at a predetermined location;

positioning and supporting the panel in a roughly horizontal position above the mask assembly;

capturing the studs and aligning and lifting the panel by means of the studs to a position where the studs are located at points which lie in a substantially horizontal stud reference plane with each stud in vertical alignment with its respective mask alignment hole and at a predetermined common vertical distance above said hole;

positioning a panel support beneath the panel to support it in its aligned position;

releasing the studs to allow insertion of the mask assembly into the panel;

compressing the mask springs to allow insertion of the mask assembly into the panel;

raising the mask assembly said predetermined vertical distance for placing the studs and alignment holes in substantial horizontal alignment; and releasing the springs to permit engagement between each stud and its corresponding alignment hole.

5. A method as defined in claim 4, wherein said mask assembly has two leaf-type springs mounted on opposing sides of the mask assembly and a third spring mounted on an adjacent side, each spring having a single alignment hole, and wherein the two opposing springs are compressed simultaneously and prior to the compression of the third spring. 

1. A method of inserting a color cathode ray tube mask assembly into a cathode ray tube front panel having a wrap-around skirt with alignment studs protruding inwardly therefrom for engagement with alignment holes formed in leaf-type springs mounted on the mask assembly, comprising: positioning the mask assembly such that the alignment holes are located at points which lie in a substantially horizontal hole reference plane, each hole positioned at a predetermined location; positioning and supporting the panel in a roughly horizontal position above the mask assembly; engaging the studs and precisely aligning the panel by means of the studs to a position where the studs are located at points which lie in a substantially horizontal stud reference plane with each stud in vertical alignment with its respective mask alignment hole and at a predetermined common vertical distance above said hole; compressing the mask springs to allow insertion of the mask assembly into the panel; effecting relative vertical movement over said predetermined distance between the mask assembly and the panel for placing the studs and alignment holes in substantially horizontal alignment; and releasing the springs to permit engagement between each stud and its corresponding alignment hole.
 2. A method as defined in claim 1, wherein the studs are located at a predetermined common vertical distance above their respective alignment holes by lifting each stud vertically a distance which effectively places it at a point which lies in the stud reference plane.
 3. A method as defined in claim 1, wherein said mask assembly has two leaf-type springs mounted on opposing sides of the mask assembly and a third spring mounted on an adjacent side, each spring having a single alignment hole, and wherein the two opposing springs are compressed simultaneously and prior to the compression of the third spring.
 4. A method of inserting a cathode ray tube mask assembly into a cathode ray tube front panel having a wrap-around skirt with alignment studs protruding inwardly therefrom for engagement with alignment holes formed in leaf-type springs mounted on the mask assembly, comprising: positioning the mask assembly such that the alignment holes are located at points which lie in a substantially horizontal hole reference plane, each hole positioned at a predetermined location; positioning and supporting the panel in a roughly horizontal position above the mask assembly; capturing the studs and aligning and lifting the panel by means of the studs to a position where the studs are located at points which lie in a substantially horizontal stud reference plane with each stud in vertical alignment with its respective mask alignment hole and at a predetermined common vertical distance abovE said hole; positioning a panel support beneath the panel to support it in its aligned position; releasing the studs to allow insertion of the mask assembly into the panel; compressing the mask springs to allow insertion of the mask assembly into the panel; raising the mask assembly said predetermined vertical distance for placing the studs and alignment holes in substantial horizontal alignment; and releasing the springs to permit engagement between each stud and its corresponding alignment hole.
 5. A method as defined in claim 4, wherein said mask assembly has two leaf-type springs mounted on opposing sides of the mask assembly and a third spring mounted on an adjacent side, each spring having a single alignment hole, and wherein the two opposing springs are compressed simultaneously and prior to the compression of the third spring. 